Before considering building my own, I’m looking for php/mysql implentations of Yahoo Answers. So far, the best examples is Askeet built by the symfony Web PHP Framework. I’m going to give it a try, but always looking for alternatives.

Scott Klarr has cheat sheets for Javascript, jQuery, Scriptaculous, MooTools, Prototype, Microsoft Ajax Library, Yahoo YUI, and Symfony. Quite a list, probably should grab these or bookmark.